1. Field of the Invention
The present invention relates to an electronic component involving a 3-terminal device, in which a capacitor and a piezo-electric device utilizing the piezo-electric effect are installed on a circuit board. More specifically, the present invention relates to an electronic component involving a 3-terminal type piezo-electric device, in which the piezo-electric device connected to first terminals, and a capacitor connected to both a second terminal and to the outside of the first terminals are firmly supported by first and second supporting means, so that the connecting work can be easily carried out, and the connection state firmly maintained, thereby upgrading the reliability of the electronic component involving the 3-terminal type piezo-electric device.
2. Description of the Prior Art
Generally, a piezo-electric device resorts to the piezo-electric effect, i.e., to a mutual converting function between the electric energy and the mechanical energy. Thus the piezo-electric device serves as the operation source for reference signals of a microprocessor. This piezo-electric device is mostly used on electronic apparatuses such as pagers, mobile communication means, televisions, audio sets and the like. At present, its demand is speedily increased. The method for manufacturing an electronic device involving the piezo-electric device includes the steps of: manufacturing a piezo-electric device; forming electrodes by depositing and patterning an electrode layer on the surface of the piezo-electric device; installing the piezo-electric device on a circuit board; and molding the component by dotting and epoxy-coating, and finishing the product by marking the device.
The 3-terminal component includes: first terminals connected to the piezo-electric device for generating a resonance frequency; and a second terminal connected to a capacitor which is necessary in the circuit. Thus the piezo-electric device and the capacitor are unitizingly packaged. Therefore, the electronic component involving the piezo-electric device can be miniaturized. Thus the 3-terminal component in which the piezo-electric device and the capacitor are simultaneously connected is widely used.
Japanese Patent Publication No. Hei-5-33847 discloses a piezo-electric device having terminals. In this conventional technique, there is provided a 3-terminal piezo-electric device in which the two terminals mutually face to each other from both ends of the piezo-electric device so as to connect the piezo-electric device, and a third terminal is connected to a capacitor.
FIG. 1 is a perspective view of terminals of a conventional 3-terminal piezo-electric device. FIG. 2 is a perspective view showing the constitution of the entire portion of the conventional 3-terminal piezo-electric component.
As shown in FIGS. 1 and 2, the above described 3-terminal piezo-electric component includes: a piezo-electric resonance device 10 having electrodes 2 installed on different faces of it and extending on the both sides of it toward center of it; and two cup shaped terminals 12 having supporting portions 16 and installed opposingly facingly at positions corresponding to the ends of the piezo-electric resonance device 10, and electrically and mechanically connected to the electrodes 2 of the piezo-electric resonance device 10 by means of a conductive coupling material; a circuit board 24 connected electrically and mechanically to the outside of the two supporting portions 16 by means of a conductive coupling material; and another terminal 28 connected electrically and mechanically to the circuit board 24 by means of a conductive coupling material.
In the above described 3-terminal type piezo-electric component, as shown in FIGS. 1 and 2, the piezo-electric resonance device 10 having the electrodes 2 is electrically and mechanically connected by means of a conductive coupling material to the insides of the two cup shaped terminals 12 which have the supporting portions 16 and are opposingly facingly positioned correspondingly to the ends of the piezo-electric resonance device 10. One electrode 26a of the circuit board 24 is connected electrically and mechanically to the outsides of the supporting portions 16, while another electrode 26b of it is connected to another terminal 28.
However, in the above described 3-terminal type piezo-electric component as shown in FIGS. 1 and 2, the piezo-electric resonance device 10 is supported by the two cup shaped terminals 12 by being mounted on stoppers 18. Electrodes 26a of the circuit board 24 which is a capacitor are connected to the outsides of the cup shaped terminals 12, while another electrode 26b is connected to another terminal. However, the circuit board 24 is connected without any separate stopper, and therefore, the connection state between the circuit board 24 and the cup shaped terminal 12 becomes unstable. Further, the other electrode 26b of the circuit board 24 is closely contacted to the other terminal 28. Therefore, although the connecting work using the conductive coupling material can be easily carried out, the soldering becomes difficult due to the lack of the melting space.
Further, the connecting work of the supporting portions 16 of the cup shaped terminals 12 and the stopper portions 18 is possible, but a perfect bending is impossible in manufacturing the stoppers 18. Therefore, during a soldering, the molten soldering material flows down.